Process of toning printing-plates.



. M. A. DROITGOUR". PROCESS 0F TONINGPEINTING PLATES.

APPLICATION FILED DEG. 15. 1910.

Patented 0Qn.1o,f19111.

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'UNITED sTATEs l.Parnrir MICHAEL A. DnoITcoun, or OAK PARK, ILLINOIS, Ass'IeNoIt Toi-iurnnnn PRINTING rRnss AND MANUFACTURING coMPANY, on CHICAGO, ILLI'NoIs A CORPORATION F III-mors.

Be it known that I, MICHAEL -DROIT- looUR, of Oak Park, in the county of. Cook Land State of Illinois, have invented certain l y'new and useful Improvements in Processes of' Toning Printing-Plates; and I .hereby declare that the following is 'a full, clear,

, and exact description thereof, reference bethinned at -those 2,5-

'to flow laterally,

lng had to the accompanying drawings, which form. p art ofthis specification.

This .inventionrelates to the production of toned or made-ready printing plates and resides in an improved method of producing suchplates.

- The object ofv this invention is to enable printing plates .to be toned withoutliability of crushing any of the ine4 lines or dots in the printing surface thereof during the toning operation. A.

-In the present lnvention instead lof the metal of the printing plate being compelled when under pressure, in Orderv to enable 'the printing plate to be toning; and all liability7 of crushing or injuring. delicate linesvor dots inthe printing surface of the printing plate during the toning thereot is practically obviated.

- In this invention I employ (l) a toning member or reverse overlay to determine the graduations er tones of the printing surface of the printing'plate; (2) a pressure grader to relieve pressure on those portions of the face of the printing 'plate where such pres-y surewould be liable to injure the same; and to obtain increased pressure on other portions of the printing plate where it is necessary in order to produce the desired tones; and (3)' al pressure plate which is provided with numerous points or projections and intermediate recesses or channels in its face opposed to the back of the printing plate whereby the metal of the. plate being toned is enabled to flow or recede into the channels ofthe pressure plate at the points Where displacement of metal is necessary in order Specification of ILetter'siatent.

l points where high lights` "are-desired, the metal .ispermitted to pass process; the

: that .the printing sur-face of the. printing fplatehmaybe .tonedin accordance with the -tones Aof vwith reference to the accompanying "drawings'which illustrate, diagrammatically, one means for utilizing the invention. In said drawings-Figure l is-an edge view of a reverse overlay or toning member, vFig. 2 represents an edge view of an `ordinary printing plate. Fig. 3 is an edge View; `of. a pressure plate; and Fig. 4 Ais a face view thereof.I `Fig. 5 is a sectional view illustrating a printing plate, a toning member, a toning pressure grader, and a presl sure plate` in a press preparatory to theapplication of pressure thereto; and Fig. 6 is a similar view showing the parts under pressure. Fig. 7 is an edge View of the resultant toned printing plate removed from the press, with the toning member applied to its face; and Fig. 8 is an edge view of thelinished toned printing plate.

The printing plate l to be toned may be an electrotype vor stereotype plate of usual construction, but preferably made about seif'en-thousandths of an inch thicker thanit `is desired to have the plate when-` finally toned and ready for use. Such plate, ,prior to the toning thereof, has a plane printing surface, as indicated in Fig. 2. From this plate a reverse overlay or toning member ,v 2 is made in any suitable manner; usually it is made of thin sheets of paper cut and pasted togetherso as to make this toning member thicker at the points where itis desired to have the plate thinner, andvice versa. In other words this reverse overlay or toning member is made thick opposite the parts of the printing plate which it is desired shall produce high lights in the impressions taken therefrom, and is made thinner opposite those portions of the printing plate which it is desired shall produc-e solids or darker shades in theimpressions.4 The toning member 2 is placed upon the face l@ of the printing.l plate l and in regis'- ter therewith; and .then the printing plate is placed face downward,- with the toning member beneath it, upon the bed 5' of a suitable press, this bed beingpreferably heated. A pressure `plate ,3, Fig- 3,;may then be placed upon the back of the plate; or may be attached, if desired, tothe 'under sur- Patented oct. 1o, 1911.4

the toning member applied thereto. 4 The invent-ion will be explained in detail` face of the platen 6 of the press. This .pres- 110 minute squares or dots enter the channels will withdraw sure plate 3 has in its lon'erliace, or Contact surface, numerous intersecting shallow channels, as indicated in Fie'. e, which chan.- Iiels may be about onesixteenth of an inch deep and extend parallel both longitudinally and transversely of the pressure member, and divide the under surface thereot into 3 each approxi` mately one-thirty-second oan inch square, and having their centers approximately onesixteenth ot an inch apart. Preterabiy the grooves in the pressure plate are slightly Wider at their mouths than at bottom, thus imparting a. slight taper or pyraniidal shape to the dots 8 so that any metal which may i'reely v therefrom.

CIK

lreterably l interpose between thebaci; of the printing plate l and the pressure plate 3, a toning pressure grader fl' (Figs. v

and G). This pressure grader may be formed like the toning member ot any suith able material; but I preferably make it of layers oit' paper grachiated according pressure necessary to effect the desired' toning ot the printing plate. ,This toning pres sure grader supplements the action of the toning member 2, being made thickerk Where the printing plate re'quires more pressure' to give the desired tone; and thinner Where the surface ot the printing plate is or such a nature that pressure would have a tend-l ency to crush or mash the saine. l'iiother words, the pressure grader 4: is a means whereby the pressure imparted by the press can be varied in its effect upon the printing plate according to the subject mattei' in said plate. The pressure grader when properly 4made will protect the weak. points of the printing,` plato, where excessive pressure would injure saine and increase the presf v sure on the printing plate Where such pres* sure is required.

Operation: The printing` plate l to be toned is placed face downward upon the bed 5 of the press, ivith the toning iii'eii'iher 2 beneath it but against its pri ting surltace; the pressure grader Il is then d upon the printing plate and against the back thereot; the pressure plate I3 is arranged or placed above the pressure grader with its clianneledi'acenext the pressure grader, see Fig. 5. rhe said parts are then t'orcibly clamped between the press bed 5 and platen 6; the bed being preferably healed to a temperature of' about 350 Sufficient pressure is applied to cause the face ot the printing plate to contorniy to the toning' member or reverse overlay applied to the :tace thereof, as the bach oi? the printing plate is inost 'forcibly pres ed lor-'ard the toning member Where. the in 1t pre is required to tone vthe printing; plaie, necausc of the nature of such printing plate, and to reproduce on the tace ot the printing tothe `reverse overlay, no

'it-ace of tlie toi'iiing` ineiiiiiier in ing plate (l5 forms in contour to -ing member messie the toning .member or twithstanding the pres any plate the tones et' sure applied to the printing plate. iniury prevented because the channels in the pressure plate provide a ready outlet jfor surplus metah. andallow metal st tlie back ot the plate opposite the projections ontlie toning member to protrude into said chanm nels, as indicated in Fig, 6; and because the metal can thus crowd bach into these channels or reeessestbere is no lateral flow o' the metal. in the printing plate suoli as heretofore been necessary when a plane surfaced pressure member was employed; hence the toning operation can be eiected with .very' much less pressure upon the printing plate than has lhitherto been re quired. fis" result oft this pressing operv ation the tace oi the printii'igg,` plate is made to reverseiy contorni to the opposed surotlier Words there will be slight depressione-i in the tace of the printinn plate at. the places the 'toning nieniberis thick, and correspond ingl projections on the hack. ol the printing plate at the points where its 'tace is de.- pressed; so that the igs. 6 and 7) suliistantially con tlme surface of the ton' vi; 2, land is uneven. To remove has Whene-l te the printing surface thereof is.

haelt et' the toned printthe inequalities troni the haelt the toned' printing plate the baci; oit the printing plate is shaved;- as indicated in Fig. 7, 1while its .tace is still in Contact 'with thevtoning me1nber 2; thereby reducing Athe back 'of the printing plate to'a plane surface, and inak- 'ing the printing plate o proper thickness for printing, while leaving the tace of the printing; l'ilate'toneul in the-desired manner. Fig. 'Y ii'idicates a toned' printing," plate removed from the press iinal sharing` operation; and' indicates at l." how the inetel has been `forced upward on the haelt' et' the printing plate into the channels et the pressure plate 3; and how the printing plate can be brought to the desired thickness by :sharing it along the line c c by a cutter C, or other suitable means, Afterward Y the toningy ineinber i2 is remove-:5l and the finished printing; plate, rep

resented in llig'. S, reinainsg-tlie suriace of this plate being toned ready for printing. l thus 'produce a printiiu;` plate havingA different 'tores `in its printiiigysurtace. :is indicated. in liif. ti. and durii r the toning operati-on the here the pressure is greatest. instr l dirthe fiat pr the ad'iiufwnt t.

thus .'ibtioi i .no pi overcoming;

l lc 'nomia-ag the e must greater pressure plate, whe-ther .such I pressen,

and ready for the print ing ice ies

lit

. tone a printing messie or less on different plate; so that Where greater pressure is necessary to tone its face I locally hold it there, and it does not laterallyliow to points Where it could damage the plate. lVhile some printing plates might be effectively toned Without the employment of the pressure grader l, yet for fine Work the most satisfactory results are obtained vby using the pressure grader 1, as the success of the toning operation is in the main, if not altogether, due to the toning pressure grader 4 in combination With the pressure plate 3 which allows for metal displacement Without lateral flow thereof. Obviously the use of the pressure plate 3 greatly lessens the amount of pressure heretofore required to plate; lessens the danger' of crushing the printing surface of the printing plate during the pressing operation; and removes the danger of distorting tine lines in the printing` surface ofthe printing-plate by lateral flow of metal therein during the toning operation.

he pressure grader 4f as above 'stated enables greater pressure to be applied to any portion of the printing plate Where it may be desired, Without affecting the tone imparted to the printing surface lof the printing plate by the toning member. It Would not do to thicken the toning member to gain increase of pressure at such points because the thickening of the toning' member would alter its toning effect upon the printing plate. But by using both a toning member and a pressure grader I can obtain the most delicate toning' effects in the face of the printing plate and at the same time obtain. any desired graduations .in the pressure upon the printing plate that Will facilitate the toning operation, and enable the same to be performed expeditiously and economically in any ordinary press. And the lemployment of a channeled pressure plate in connection With the toning member and pressure grader loca-lines excessive pressure on the printing plate by obviating lateral flow of the metal therein, which otherwise would tend to flow laterally and'distribute the pressure equally throughout the printing plate.

lha-t I claim is:

l. The method of toning linished printing plates, consisting in applying a toning member to the printing surface of such printing plate, applying a channeled pressure plate against the back of such printing plate, and subjecting these parts to pressure whereby the face of the printing plate is caused to reversely conform to the surface of the toning member by reason of the metal on the back of the plate being permitted to parts bf the printing y the toning lsaid parts to flow or pass directly into the channels 1n the face of the pressure plate at those points Where displacement of metal is necessitated Without lateral flow of the metal.

2. The herein described process of toning printing plates, consisting in applying a toning member to the face of a printin plate, applying a pressure grader to the back thereof, and then subjecting the said parts to pressure suicient to cause the printing surface of the printing plat-e to reversely conform to the toning member.

3. The herein described process of toning printing plates, consisting ing member to theface of a printing plate, applying a pressure grader to the back thereof, applying a pressure plate having a channeled surface to the pressure grader, and then subjecting said parts to sufcient pressure to cause the printing surface of the printing-plate to reversely conform to the opposed surface of the toning member.

4f. The herein described process of toning printing plates, consisting informing a flat surfaced printing plate, applying a toning member to the face thereof, applying a pressurev grader to the-back thereof, applying a pressure plate having achanneled surface against the pressuregrader, and then subjecting the said parts to pressure sufficient to cause the printing surface of the printing plate to reVe'rsely conform to member; the metal at t-he back of the plate passing into the channels in the pressure plate at the points Where displacement of the metal is necessary to eHect toning of the printing plate in accordance with the toning member. v

The herein described process of toning printing plates, consisting in forming a flat surfaced printing plate, applying a reverse overlay to the `face thereof, lapplying a pressure grader to the back thereof, applying a pressure plate having a channeled surface to the pressure grader; then subject-ing the pressure to cause the printing surface of the printing plate to reversely conform to the opposed surface of the reverse overlay, and surplus metal in the back of the plate to flow into the channels in the pressure plate at those points placement of the metal necessary to effect the toning of the printing plate; and finally reducingjthe back of the printing plate to a. plane surface.

In testimony'vthat I claim the foregoing as my own, I aliizr my signature in presence of two Witnesses.

. MICHAEL A. DRITCOUR.

-lVitnessesz a SIMON Bannon?, Pnncr Gf. SHAW.

|Where disin applying a ton- ,y 

